1. Field of the Invention
The present invention pertains generally to land vehicles, and more particularly to wheeled, articulated vehicles constructed to accommodate a boat for transport. In an even more particular manifestation, the invention pertains to self-loading pontoon boat trailers.
2. Description of the Related Art
Boats of all sorts and types, used variously for leisure, sport and commerce, are transported upon an equally diverse collection of trailers. Trailers offer a number of benefits over transporting a boat directly upon an automobile, sport utility vehicle, pick-up truck, flat-bed truck, or the like. Among these benefits are loading and unloading the boat at an elevation closer to the ground; the ability to unload the boat directly into a waterway and reload the boat therefrom while still maintaining vehicle drive wheels upon dry ground for good traction; ready storage by simply unhitching the trailer from the vehicle, with associated rapid and simple retrieval from storage; and the ability to load and transport boats much longer than the motor vehicle. Since in some instances the boats are loaded or unloaded on a daily basis, these trailers most preferably simplify the loading and unloading process.
One of the more common techniques for supporting a boat upon a trailer uses rollers, which assist a person greatly with the loading and unloading of the boat. A hand or powered winch may be provided which draws the boat onto and across the rollers. Since the rollers are able to roll across the exterior of the boat, such as along the keel or along the port or starboard undersides, there is almost no scraping or sliding of the boat which would otherwise damage the boat, and there is very little force required to move the boat over the rollers. Consequently, a winch and cable may be hand-turned in many instances, and such winch and cable are generally relatively low cost commodity items.
While the rollers tend to simplify the loading and unloading of a boat, they do not provide good support for the boat. This is because the rollers normally have very little surface area in contact with the boat hull. At the point of contact, the forces placed upon the boat bull by the total weight of the boat and contents may cause the boat hull to deform. Even absent noticeable deformation, the stresses generated adjacent a roller tend to be very high, leading to premature failure of the boat hull. While additional contact may be obtained with the use of more rollers, which would thereby reduce the stress between the boat and any given roller, rollers tend to be relatively expensive. Consequently, supporting more than a very minor amount of surface area on the boat with rollers is cost prohibitive.
In contrast, another common technique for supporting a boat upon a trailer uses bunks, which are solid surfaces against which a boat hull is rested. In the case of a bunk trailer, the boat hull is solidly supported across the entire bunk, rather than across a few square inches of roller. Since the bunk is very low-cost, typically comprising little more than a beam having a non-marring surface, the cost of supporting a large surface area is quite small. This in turn leads to much better transport, including a substantial reduction in the stress forces generated within the boat hull and a resultant reduction in the likelihood for damage to the boat during transport. Unfortunately, this type of trailer creates much greater friction between the bunk and boat during loading and unloading, thereby necessitating a much more powerful winch. Additionally, should any foreign particles or devices or substances work their way between the boat hull and the bunk, these particles may cause substantial damage to the boat hull.
In some cases, prior art trailers are designed to accommodate several different types of boats with distinct hull designs. However, most trailers are designed for only one or a limited few types of boat hulls. For example, a trailer designed to carry a typical fishing boat will be shaped to accommodate the relatively deep keel and steeply sloping sides of the boat. In contrast, a shallow water boat or jon boat is designed with a relatively flat bottom. Consequently, a carrier designed to receive the keel and steep sides of a fishing boat will not receive and support a flat-bottom boat. The same holds true for other diverse types of boats, such as catamarans and pontoon boats, each which also have unique hull designs. These and other types of boats have consequently required specific trailer designs or accommodations.
In the specific case of a pontoon boat, the boat will generally include two or more pontoons, which are elongated tubes that may typically be sealed and hold air or another gas therein. Most commonly, across the top of the pontoons there will be attached a deck which supports passengers, a boat engine, and other various components, while simultaneously fixing the position of the pontoons relative to each other.
Pontoon boats have presented some challenges to trailer design that are relatively unique, for which desirable solutions have heretofore been elusive. Among these are the wide spacing of the pontoons. The pontoons, which are generally among the lowest components of a boat, are placed adjacent the edges of the deck in order to provide optimum floatation for passengers who may also be standing adjacent the deck edge. This spacing between pontoons makes for safer boating. Unfortunately, it also makes trailer design somewhat more difficult than with other types of boat hulls. This is because any support for a boat upon a trailer will most preferably be at the outer edges of the boat, so that as the trailer is turning a corner, for example, the boat is securely supported and does not tip over. Unfortunately, in the case of a pontoon boat and bunk trailer, support adjacent the outer edges of the boat also means raising the boat somewhat more off of the ground than would be required for a support more centrally located. Consequently, the elevated support may tend to be more difficult to load, and will typically require a relatively deep boat landing in order for the trailer to drop far enough for the pontoons to float off of the trailer.
Further limitation stems from the fact that unloading the boat from a prior art bunk trailer upon dry land is only practical if the operator has access to a small fork lift, skid steer or the like. The weight of a pontoon boat is measured in the thousands of pounds. The pontoons themselves, when resting upon the bunks, will not readily slide. Loading presents the same dilemma, since the pontoons will not slide along the earth. Consequently, an automobile will more readily slide along the ground than the pontoon boat. Winching the boat onto the trailer is therefore not practical.
To resolve these difficulties, another type of trailer has been designed specifically for pontoon boats, referred to in the prior art as a scissors-type trailer. Scissors trailers operate similar to a scissors jack, where the movement of a screw is used to separate or bring together two base elements. The spreading of these base elements will generally lower the trailer top, and a boat supported thereon, closer to the ground. Bringing the elements together will, through the scissors mechanism, raise the top of the trailer and the supported pontoon boat. With these scissors trailers, several distinct benefits and advantages are obtained in the transport of pontoon boats that are not available with bunk trailers. Most important to many pontoon boat owners is the ability to load and unload the pontoon boat in extremely shallow waters, or directly from the ground. Rephrased, the scissors trailer is designed to slip in the space between pontoons immediately under the deck, and then is used to jack the pontoons upward off of the ground or out of the water sufficiently to allow the boat to be transported safely. Unfortunately, since the trailer must first pass between the pontoons, the transverse distance across the trailer between wheels is significantly less than the width of the pontoons. Any significant elevation provided by the scissors trailer tends to make the trailer much more inclined to roll over, since the weight of the boat extends outside of the trailer wheels. Such roll-overs have the potential for causing great harm not only to the supported pontoon boat, but also to other persons and property which the boats would then collide with.
U.S. Pat. No. 5,292,145 by Ostrand, the contents which are incorporated herein in entirety by reference for the teachings of trailer and roller construction, illustrates a prior art trailer for a standard fishing boat or the like that supports a boat upon roller assemblies during loading and unloading and uses bunks for transport. In the Ostrand patent, an operator-activated motor-driven actuator retracts the rollers to allow the boat to rest upon bunks during transport. While the Ostrand patent may, at least in principal, appear to address one of the concerns of the prior art by combining bunks and rollers, this patent does not offer any benefit or advantage for loading and unloading adjacent the ground. Furthermore, two separate motive power devices are required to control this trailer. The first device is the winch, which is used to pull the boat onto the trailer. The second is the actuator, which is used to engage and disengage the rollers. There is no attempt to integrate these two separate functions into one, nor to assist with ground-level loading. Consequently, to load a boat with the Ostrand trailer, an operator must first back the trailer sufficiently under the boat to engage the rollers. Noteworthy here is the fact that, in practice, the level of the elevated rollers is the exact same level required for the boat to clear the bunks in the first place. In other words, during water launching and loading, the Ostrand rollers add no value to the trailer, since the operator will float the boat off of or onto the bunks. Since on dry land the boat must be raised to the elevation of the trailer, the rollers illustrated therein also add very little to a dry land loading and unloading. Consequently, the additional structure and expense offers very limited value in actual practice, while adding substantial cost and expense. Additional documents incorporated herein by reference for related teachings include U.S. Pat. No. 5,152,657 by Kehne; U.S. Pat. No. 5,133,571 by Urbank; U.S. Pat. No. 5,013,206 by Ernst et al; U.S. Pat. No. 5,004,260 by Smyly; and U.S. Pat. No. 3,768,677 by Moss, though none illustrate or teach the features and benefits of the present invention.
In a first manifestation, the invention is a boat trailer having support bunks which are active during boat transport for supporting a boat in combination with rollers that are moved during loading and unloading into an active position. The trailer includes a trailer bed with a ground-engaging wheel and a boat support frame having support bunks and rollers supported thereon. A pivot between the boat support frame and trailer bed allows the boat support frame to rotate relative to trailer bed. An actuator elevates the rollers relative to boat support frame responsive to a rotation between the boat support frame and trailer bed.
In a second manifestation, the invention is a method of loading a pontoon boat onto support blocks supported on a support frame of a trailer. The method includes the steps of pivoting the frame relative to the earth about a first axis in a first direction of revolution; moving a low-friction support to a first position of engagement with the pontoon boat, said first position of engagement occurring prior to a second position of engagement between support blocks and pontoon boat; engaging the low-friction support with pontoon boat; maintaining low-friction support in first position of engagement responsive to the engaging step; displacing the pontoon boat relative to the low-friction support subsequent to the engaging step to thereby redistribute forces applied to the frame; pivoting the frame in a second direction of revolution opposite to the first direction of revolution responsive to the redistributed forces; and moving the low-friction support from the first position of engagement to a third position of engagement occurring subsequent to the second position of engagement, whereby the pontoon boat is supported upon the support blocks.
In a third manifestation, the invention is in combination, a pontoon boat having a deck and a plurality of pontoons thereunder with a pontoon trailer. The pontoon trailer includes a wheel carriage; a pivot axis; and a support carriage adjacent the wheel carriage and pivotal relative thereto about the pivot axis. The support carriage has a plurality of bunks for carrying a pontoon boat during transport. An actuator is anchored to the support carriage at a first end and to the wheel carriage at a second end for producing an actuating movement responsive to a pivotal motion between wheel carriage and support carriage. A roller set is positioned relative to support carriage responsive to the actuating movement between a first position carrying the pontoon boat and a second transport position releasing the pontoon boat.
Exemplary embodiments of the present invention solve inadequacies of the prior art by providing a self-loading and unloading trailer which can be operated by a single person to load a boat from difficult boat ramps or even directly from the ground. The trailer provides rollers for engaging the boat during loading and unloading of the boat, but safely rests the boat on bunks during transit. By incorporating the features of the present invention, the advantages of using a trailer for boat transport across land are preserved. These advantages include but are not limited to ready storage and rapid and simple retrieval from storage; and the ability to load and transport boats much longer than the motor vehicle.
A first object of the invention is to enable relatively safe loading, unloading, and transport of a pontoon boat using a trailer, and preserving the benefits attainable therewith. A second object of the invention is to load and unload a pontoon boat at ground level. Another object of the present invention is to unload a pontoon boat directly into a waterway and reload the boat therefrom while still maintaining vehicle drive wheels upon dry ground for good traction. A further object of the invention is to substantially reduce stress forces generated within the boat hull during loading, unloading and transport, to reduce the likelihood of damaging the boat during transport-related activities. Yet another object of the present invention is to alleviate damaging friction between bunk and boat during loading and unloading, while still obtaining the benefit of a bunk during transport. An additional object of the invention is to enable a single person to load, transport and unload a boat using the various embodiments of the invention.